.w{
    width: 1200px;
    height: 100%;
    margin: 0 auto;
    background-color: chartreuse;
}
.header{
    width: 100%;
    height: 45px;
    background-color: blue;
}
.header1{
    position: relative;
    position: relative;
    height: 45px;  
}
.header11{
    position: absolute;
    top:9px;
    float: left;
    width: 22px;
    height: 29px;
    background: url(../img/logo.png);
}
.header12{
    float: right;
    width: 500px;
}
.header121{
    height: 29px;
    float: left;
    margin: 0 30px;
    line-height: 45px;
}
.header122{
    width: 100%;
    height: 2px;
    padding-bottom: -2px;
    background-color: black;
    display: none;
}
.header123:hover header121{
    color: grey;
}